On Visual Builder was defined several service connections with different query parameters set and between all the parameters defined, the "fields" parameter that is configured to "extract" a restricted subset of fields in the response.

Then it was defined for the the Service connection Name = "Activities" and for the endpoints getall_activities, in Request-> URL Parameters, defined the request's Query parameters "fields" with the following values :

Name Type Default Valuefields String DueDate,ActivityType,Subject

After this, the default value was modified, and three more fields were added: ActivityId,AccountId,ActivityNumber; stepping off the text input.

The message bar displays the "saved message" with the timestamp. If a test is run, one can see the response with the additional fields added.However if one returns to the application list and then navigates back to the service endpoint definition the additional fields previously added disappear.There is no error on the UI, but the fields mentioned above go missing after refresh.